Tube transmitter keying method



Oct. 27, 1931. E, TOD 1,828,852

TUBE TRANSMITTER KEYING METHOD Filed July 11, 1925 INVENTOR ERKIH IOD TORNEY Patented Oct. 27, 1931 UNITED STATES PATENT OFFICE ERICH TOD, OF BERLIN, GERMANY, ASSIGNOB TO GESELLSCHAFT FU'R DRAHTLOSE TELEGRAPHIE M..B. BL, OF BERLIN, GERMANY, A CORPORATION OF GERMANY TUBE TRANSMITTER KEYING METHOD Application filed July 11, 1925, Serial No. 42,864, and in Germany July 25, 1924.

In keying tube transmitters for short waves, say, of 150 meters and less there occur variations in the length of the wave through interrupting the direct current of the grid.

The present invention eliminates these variations in the wave length by the use of the hereinafter described keying method.

To the aerial is coupled an oscillatory circuit which during the in'termissions in tele graphing is tuned to the wave length in question and which draws energy from the aerial, whereas during telegraph signalling it isdetuned or interrupted. In this way the tube i transmitter circuit load is always practically constant.

A simple plan, as shown diagrammatically in the drawing forming part of this specification, is to open or close the absorption circuit for the object of keying. In the drawing 1 denotes the tube transmitter, 2 the aerial to which the absorption circuit 3 is connected which can be closed or opened by the aid of the key 4. On opening the key 4:, in the arrangement according to the illustration, unusual sparking does not occur. The reason for this is as follows:

In normal state, a certain quantity of energy is put into the antenna 2 from the oscillation circuit of generator 1,.and this quantity of energy is dependent upon the resistance which can be conceived as being transferred from antenna 2 to the circuit 5. By coupling the absorption circuit 3, by the closing of the key t, to the antenna 2, a high resistance is transferred from circuit 3 to the antenna circuit 2, under the assumption that the self resistance of circuit 3 is very low. In this manner the electrical conditions have been so altered that in this state only a very small fraction of energy is transferred from generator 1 to the antenna circuit, with the consequence that due to the limiting of such energy flow no energy can nowflow any" longer into the circuit 3. The interruption or opening of the key 4, therefore, will then take place practically in the absence of sparking. I

What I claim and desire to protect by Letters Patent is:

1. In a wireless transmission system in combination with a high frequency'oscillation generating circuit including a thermionic generator having input and output electrodes and an oscillation circuit connectedto the output electrodes thereof, an aerial circuit coupled to said oscillation circuit, a tuned circuit including an inductance coupled to an inductance in said aerial circuit, said circuit being normally adapted to transfer a resistance effect to said antenna and from said antenna to said oscillation circuit, and means for completely interrupting said tuned circuit whereby, when said circuit is open, sig-' nals are generated by said oscillation generator and radiated from said aerial, and

when said circuit is closed no current flows in said tuned circuit.

2. In a wireless transmisslon system in combination with a high frequency oscillacircuit connected between the anode and Y cathode thereof and inductively coupled to an oscillation circuit connected between the control electrode and cathode thereof, an;

ERICH TOD. 

